Returns a list of IS objects defining a decomposition of a problem into subproblems corresponding to different fields: each IS contains the global indices of the dofs of the corresponding field. The optional list of DMs define the DM for each subproblem. Generalizes DMCreateFieldIS().

Synopsis

Input Parameter

Output Parameters

- The number of subproblems in the field decomposition (or NULL if not requested)

namelist

- The name for each field (or NULL if not requested)

islist

- The global indices for each field (or NULL if not requested)

dmlist

- The DMs for each field subproblem (or NULL, if not requested; if NULL is returned, no DMs are defined)

Notes

The user is responsible for freeing all requested arrays. In particular, every entry of names should be freed with
PetscFree(), every entry of is should be destroyed with ISDestroy(), every entry of dm should be destroyed with DMDestroy(),
and all of the arrays should be freed with PetscFree().